Self-standing bottom base broadened pouch

Abstract: A flexible, self-standing pouch (1) and a method for making the same. Said pouch has a top (2) and a base portion (3) comprising a front wall (4), a back wall (5) and a base wall(6). The pouches according to the present invention comprise peripheral edges in said base portion which are oblique.

Description: Technical Field of the Invention The present invention relates to self-standing flexible pouches for containing liquids or fine granules, particularly liquid detergents. Background of the Invention The use of flexible standing pouches for containing liquids is well known in the packaging industry. However, such pouches are prone to instability problems, such as the inability to retain an upright position when filled. In order to try and overcome this problem the art describes pouches produced from thick and thus more expensive material. Many pouches described in the art frequently require a means of support such as a frame in order that the pouches stand upright. Indeed, even pouches produced from thick material may often also require additional support means so that they maintain an upright position. Other pouches that are disclosed in the art, commonly referred to as Doypacks are designed so that in the upright position the pouches stand on the pouches' bottom edges, so that the majority of the base wall is not in contact with the surface. However, such pouches are prone to the weakening of the bottom edges of the pouches over time, resulting in the eventual collapse of the bottom edges and loss of upright stability and ultimately the collapse of the pouch itself. FR-A-2 417 440 discloses a pouch according to the preamble of claim 1, comprising peripheral edges of the front wall, back wall and base wall in the base portion of said pouch sealed and cut in oblique manner. This improves the self-standing of said pouch. US-3 380 646 describes a method for making a Doypack, according to the preamble of claims 7 and 8. Thus, a principle object of the present invention is to provide a flexible pouch for containing liquids which is self-standing. A further object of the present invention is to provide a flexible pouch which is sufficiently stable to allow a consumer to firmly grasp and pour out the contents of the pouch with confidence. Another object of the present invention is to reduce the amount of material from which the pouches are manufactured. Additionally the pouch material should collapse when discarded and thereby reduce the volume of generated waste material. Yet a further object of the present invention is to provide a pouch from a material which is lightweight but strong and robust. Another object of the present invention is to provide pouches which can be manufactured by simple adaptation of the existing manufacturing methods used for Doypacks. Summary of the Invention The present invention is a self-standing flexible pouch for containing liquids according to claim 1. The present invention also relates to a method of making said pouch, as claimed in claims 7 and 8. Brief Description of diagrams It is believed that the invention will be better understood from the following detailed description with reference to the diagrams in which: Fig. 1: front view of an unfilled pouch of the present invention. Fig. 2: cross-sectional side view of portion of an unfilled pouch of the present invention. Fig. 3: side view of a filled pouch of the present invention. Fig. 4: perspective view of the sheets used for manufacturing the pouches of the present invention. Fig. 5: perspective view of the various members of an apparatus for carrying out the method used for the sheets in Fig. 4 Fig. 6: cross-section of a tube of plastic material used for the manufacture of the pouches according to a modified method. Fig. 7: perspective view of the members of an apparatus for manufacturing the pouch with the tube of Fig. 6. Fig. 8: front view of an unfilled pouh with severed bottom corners. Fig. 9: side view of a filled pouch showing a preferred unfolding of the bottom seal. Detailed Description of the Invention The present invention relates to a flexible pouch (Fig. 1, 1) for containing liquids. The pouch is stable and self-standing without the need for additional support means. The pouches according to the present invention have a top portion (Fig. 1, 2) and a base portion (Fig. 1, 3) comprising a front wall (Fig.1, 4), a back wall (Fig. 1, 5) and a base wall (Fig. 1, 6). According to the present invention the base wall is generally perpendicular to the front and back walls when the pouch is in its filled upright position. The top portion (Fig. 1, 2) of the pouches according to the present invention comprises said front (Fig. 1, 4) and back walls (Fig. 1, 5) which are superimposed upon one another. The front and back walls are sealed together along their top edges (Fig. 1, 7 and 8) and their peripheral edges (Fig. 1, 9, 10 and 11, 12 )only in said top portion. The seals in the pouches according to the present invention are preferably heat seals. Said seals are preferably from 3mm to 50mm, more preferably from 3mm to 10mm, most preferably 5mm in width. The base wall (Fig. 2, 21) is foldable into a pleated inverted V shape and is situated in between said front (Fig. 2, 22) and back walls (Fig. 2, 23). The inverted V shape may be continuous with the front and back walls, such that all the walls of the pouch are formed from one single foil of pouch material. As an alternative said base wall may be an additional piece, separate from the front and back walls, which is further sealed at one bottom edge of said base wall with the bottom edge of the front wall and sealed at the other bottom edge (Fig.2, 24) of said base wall with the back wall in the base portion of the pouch . Each half of the pleated inverted V shape forms a corresponding leg with the front (Fig. 2, 25) and back walls (Fig. 2, 26) when the pouch is unfilled. The peripheral edges of said base wall are sealed to the peripheral edges of the corresponding front (Fig. 2, 27) or back wall (Fig. 2, 28) in the base portion. The section of the base wall not sealed to the front and back walls, is such that the midsection of the base wall (Fig.2, 29) is free and may extend up into the interior of the pouch when the pouch is unfilled. According to the present invention it is essential that said base wall is sealed to said front wall peripheral edge (Fig.2, 30) and said back wall peripheral edge (Fig.2, 30b) in said base portion with oblique seals. All of the peripheral edges of said front and back walls and said base wall in said base portion are substantially along said oblique seals. Said oblique edges are substantially parallel with said oblique seals. According to the present invention said oblique seals improve the stability of the pouches when filled. Oblique as used herein is determined with reference to the perpendicular axes (Fig 1, 13a,13b) which extend from the top portion of the pouch along the inner edge of the seals of the peripheral edges of the front and back walls when the pouch is filled in its upright position into the base portion. An oblique seal or oblique peripheral edge according to the present invention is a seal or peripheral edge which does not lie along said perpendicular axes, but is inclined away from said perpendicular axes towards the bottom edge (Fig.1, 14) of the base portion (Fig. 1, 3), so as to form an obtuse angle (Fig. 1, β) between the inner edge of the seal of the peripheral edge of the top portion and the corresponding inner edge of the peripheral edge of the base portion. According to the present invention the obtuse angle is preferably from 90° to 180°, more preferably from 120° to 150°. In a preferred embodiment (Fig.1) the pouches according to the present invention have dimensions which are determined by said obtuse angle (Fig.1, β). It has been found that in a preferred embodiment of the present invention, it is the pouch dimensions themselves that determine the distribution of the pouch contents and thus the overall stability of the pouch when filled. If the distribution of the liquids in the pouches is unequal then creases and/or crevices and/or folds occur, distorting the shape of the pouch, which contributes to instability. In a preferred embodiment of the present invention wherein; w = width of front or back wall y = width of seals attaching the peripheral edge of the front wall and the peripheral edge of the back wall of the top portion of the pouch x = half the width of the base wall when the pouch is unfilled b = length of bottom edge of the base portion β = obtuse angle between the inner edge of the oblique peripheral seal of the front or back wall in the base portion and the perpendicular axes.(see fig. 1) the pouch has dimensions wherein x is preferably from 10mm to 1000mm, more preferably from 50mm to 300mm. Y is preferably from 3mm to 50mm, more preferably from 3mm to 10mm, most preferably 5mm. w is preferably from 50mm to 1000mm, more preferably from 50mm to 500mm, most preferably 250mm. b is form 0mm to 1000mm, preferably from 50mm to 500mm, more preferably from 100mm to 200mm. It has also been found that in a preferred embodiment of the present invention, the position of the centre of gravity of the filled upright pouches is determined by the overall dimensions of pouches. According to the present invention the dimensions are preferably such as to lower the centre of gravity to a point in the base portion of the pouch. According to the present invention base wall is substantially perpendicular to the front (Fig. 3,2) and back (Fig.3,3) walls when the pouch is in its filled upright position so that a substantial part of the base wall is in contact with the surface upon which the pouch stands (Fig.3,1). In another preferred embodiment of the present invention the bottom seal corners (Fig. 1, 16) and (Fig. 1, 16b) between the oblique seal (Fig. 8, 100) and the horizontal seal (Fig. 8, 110) are severed in another oblique manner (Fig. 8, 112a, 112b). This reduces the thickness (Fig.8, 120) of the seal in this part, introducing a weak point. It has been found out that said weak point ensures that the bottom horizontal seal part (Fig. 8, 110) unfolds outwardly, avoiding said horizontal seal part to be caught under the base wall (Fig. 9, 140) of the pouch. This improves the pouch stability. It has been found that creasing the bottom horizontal seal part (Fig. 8, 110) during pouch forming and/or embossing just above the bottom horizontal seal part (Fig. 8, 110), further improves the pouch stability. In practice, a film tension is introduced in these manners in or just above the bottom horizontal seal part (Fig. 8, 110). Said tension forces the horizontal seal part (Fig. 8, 110) to unfold outward when the pouch is filled with product. Another possibility to improve the pouch stability is to use a stiffer material for the base wall (Fig. 9, 140) than for the front (Fig. 9, 120) and back walls (Fig. 9, 130). Stiffer material can be achieved through usage of a different plastic type and/or thicker laminate structure. All the improvements mentioned above, i.e. the severed part between oblique (Fig. 8, 100) and horizontal seal part (Fig. 8, 110), the introduction of film tension or the usage of stiffer material, help to flip the bottom seal (Fig. 9, 150) outwards, therefore to improve the stability of the pouch. The improvements can be used independently or in any combination in any embodiment of the present invention. In a preferred embodiment of the present invention the pouches may have at least one, preferably 1 to 4 vertical ridges on the front and back walls of said pouch, (Fig. 1, 15) when the pouch is in its filled upright position. The ridges preferably extend from the bottom edge of the base portion corners (Fig.1 16, 16b) vertically up at least into the top portion of the pouch. Said ridges are preferably parallel with the perpendicular axes (Fig.1, 13, 13b). The ridges according to the present invention preferably extend at least 50% of the length of the front and back walls, when the pouch is in its upright position, preferably from 50% to 90%, more preferably from 70% to 90%. The ridges give the pouches the desired configuration in at least the base portion and help retain said configuration. The ridges also help the base wall to remain in contact with the surface upon which the pouch stands and helps stiffen the pouches. Preferably the pouches of the present invention have a substantially rectangular footprint in at least the base portion of said pouches. In another preferred embodiment of the present invention the pouches comprise a handle (Fig.1, 17) in the top portion of said pouch. The handle is a sealed corner of the front and back walls in the top portion of said pouch. Said sealed corner is the corner between the top edges (Fig.1 ,7,8) of the front and back walls and one of the peripheral edges of said front (Fig.1, 11) and back (Fig.1,12) walls in the top portion such that the front (Fig.1,4) and back walls (Fig.1,5) are sealed together beyond their edges. A piece of the sealed portion is removed from the centre of said sealed portion so that an opening (Fig. 1, 18) is formed to enable a consumer to place the fingers through said opening. Said opening is preferably oblong and substantially parallel with the bottom edge of the seal (Fig.1, 19). The top edge of the seal of the handle (Fig.1, 20) is preferably parallel with the edge of said opening and said bottom edge of the opening seal. Suitable materials for use as the front, back and base walls according to the present invention are preferably thin, to reduce the amount of material used and the associated cost, whilst being sufficiently thick, and tough enough to resist punctures and leaks caused by abrasion and rough handling. Preferably the pouch material is from 50 micrometers to 500 micrometers, more preferably from 100micrometers to 300micrometers. The front, back and base walls are also selected from materials that can be easily handled and sealed together, preferably by heat sealing in a high-speed form, fill and seal apparatus. Suitable flexible materials for use herein may be selected from thermoplastics, preferably polyethylene, most preferably linear low density polyethylene (LLDPE). According to the present invention the front, back and base walls are preferably made of the same material. As discussed before, it may be preferred to have a stiffer material in the base wall (Fig. 9, 140), than in the front (Fig. 9, 120) or back walls (Fig. 9, 130). For example, using LLDPE for the front and back walls a middle density polyethylene (MDPE) coextrude can be used for said base wall. According to the present invention the plastic material may be a composite material constituted by at least two layers of different plastic materials such that one of said material is thermally weldable while the other is not. By laminating LLDPE with a thicker layer of polyethylene terephthalate (PET) or oriented polypropylene (OPP) than for the front (Fig. 9, 120) and back walls (Fig. 9, 130), a stiffer material in the base wall (Fig. 9, 140) can be also achieved. For example, the front and back walls can be made of 180 µm of LLDPE and 12 µm of PET, whereas the base wall can be made of 220 µm of LLDPE and 12 µm of PET. This example shows only a possible way of execution and is by no way limiting the present invention. According to the present invention the pouches may be filled with solids or fluids such as food products, laundry detergents, softeners, automatic dishwasher detergents and hard surface cleaners. Preferably the pouches of the present invention are filled with liquid detergents. According to the present invention one of the corners of the top portion of the pouches may be removed to provide an opening so that the consumer can pour out the contents of the pouch. Pouches of the present invention may be used as sample pouches and refill pouches for reusable containers. The pouches according to the present invention may be manufactured according to the methods well known to the man skilled in the art and described in US 3 380 646. The process may be a continuous, a semi-continuous or a multi-step batch process. The flexible self-standing pouches according to the present invention may be produced by a number of methods two of which are described below: As shown in Fig. 4 and 5 the pouches are produced at the start from three strips of plastic material (Fig.4, 1,2,3) respectively. The two strips (Fig. 4. 1 and 2) have the same width and are superposed. The strip (Fig.4, 3) which may be of a different nature and thicker than the other two strips, is much narrower and doubled up so as to form an inverted V of which the two edges are juxtaposed with two longitudinal edges of the strips (Fig.4, 1 and 2). Said strips (Fig.4, 1, 2 and 3) may be made of any plastic material unitary or composite. In the case where the material is of a composite type, it consists of two layers of plastic material of different character such that one of them is thermally weldable, while the other is not. The seals executed perpendicularly to the axis of the strips (Fig.4, 1,2) and (3), will join together the strips (Fig.4, 1, 2) throughout the height of the upright pouch thereof and the doubled up strip (Fig.4, 3), said seals being those (Fig.5, 6) which will define the container laterally; It is essential that the seals executed on the strips (Fig.4, 1, 2) and the strip (Fig.4,3) will only unite the strip (Fig.4,1) to one of the faces of the strip (Fig.4,3) and the strip (Fig.4,2) to the other face of said strip (Fig.4,3) as a result of the composite character of said strips (Fig.4,1, 2): the seals (Fig.5, 4 and 5) will define the bottom part of the container and suspend said bottom part of the lateral seals (6). With reference to Fig. 5, (7, 8) indicate the two reels which deliver the strips (Fig.4,1 and 2) respectively, which pass through the bar means 9 which enable said strips to travel then over in the other direction of the arrow (10) through the agency of a pulling systems (not shown). (Fig.5, 11) indicates another reel of which the axis is vertical, that is perpendicular to the axes of the reels (Fig.5, 7 and 8). Said reel (Fig.5,11), delivers the narrow strip (Fig.4,3) which passes through bar means (Fig.5, 12) which make it possible for said strip to double itself up so far as to form an inverted V, after which said strip (Fig.4, 3) passes through the bar means (Fig.5, 9) between the two corresponding longitudinal edges of the strips (Fig.4, 1 and 2). Two complementary electrodes (Fig.5, 13) are disposed downstream with respect to the bar means (Fig.5, 9) and are adapted to move in a direction perpendicular to the travel of the strips (Fig.4, 1, 2 and 3). The electrodes (Fig.5, 13) have dimensions and their operating rhythm is such that they form oblique seals (Fig.5, 4) and the horizontal seals (Fig.5, 5) in the area where the strips (Fig.4, 1, 2 and 3) are superposed. Downstream with respect to the electrodes (Fig.5, 13) is another pair of electrodes (Fig.5, 14) which are intended to execute the seals (Fig.5, 6). After passing between said electrodes the pouches pass through a set of blades (Fig.5, 27, 16). Said blades (Fig.5, 27) cut along the edge of the oblique seals (Fig.5, 4) and the strips (Fig.4, 1, 2, 3), thus forming oblique edges and thus define several pouches which are severed from one another by said set of blades (Fig.5, 16). The arrangement described herein above may be used for the manufacture of pouches according to the the present invention where a composite material is used or a pouch material which thermally weldable on one face only. When using a unitary material or a non composite plastic material, or even a composite material of which both faces are thermally weldable, said arrangement is not suitable as the oblique seals (Fig.5, 4) and the horizontal seal (Fig.5, 5) would join together the four plies formed by the strips (Fig.4, 1, 2, 3) which would prevent the formation of the bottom portion of the pouch. In such an instance a set of anti adhesive screens or shields (not shown) are disposed, the length of which is greater than the width of one pouch, said screens being disposed opposite each other. Said screen prevents the sealing of the front leg (Fig. 2,25) to the back leg (Fig. 2,26). Fig. 7 illustrates, by way of example an apparatus for manufacturing a pouch according to the present invention from non-composite material. At the start, said material may be in the form of superposed strips, or folded sheet or a folded in tube. Fig. 6 and 7 illustrate the latter instance. The pouches are produced from either three foils of plastic material, which constitute the front, back and base walls or a folded foil or a folded in tube. Fig. 7 illustrates the latter instance and indicates a reel (17) delivering a flattened tube of plastic material (18) of which both edges are folded in a manner such that each edge forms a V section (19). On the path of the tube (18) in the direction of the arrow (20), two anti-adhesive screens (21) are disposed, the length of which is greater than the width of one pouch, said screens being disposed opposite each other inside the lateral folds (19) of the tube (18). On either side of each of said screens (21) two electrodes (22) are located and are adapted to move within a plane perpendicular to the direction of the direction of the travel of the tube (18). When the electrodes (22) close and squeeze the edges of said tube (18) they form the oblique seals (4) and the longitudinal seal (5) and owing to the presence of shields or screens (21), these seals unite only one of the faces of the tube (18) to the corresponding inner faces of the tube to the corresponding inner face of the fold (19), although both faces of said tube are made of thermo-sealable material. A second set of electrodes (23) are located downstream or forwardly of the electrodes (22) and form the lateral seals (6) on each pouch. Downstream of the electrodes are located sets of blades (24, 26) and a cutting device (25). The first set of said blades cuts along the edge of the bottom of the oblique seals (4). The second set of said blades cuts the tube along the median longitudinal line thereof. Said cutting device (25) severs the pouches from one another. The apparatus for manufacturing a pouch according to the present invention illustrated by Fig. 7 may also be used to manufacture pouches made of composite material or material which is only thermally weldable on one of its faces by removing the anti-adhesive screens (21). In a preferred embodiment of the process of the present invention illustrated in Fig. 5 there is located upstream of the electrodes (23) heating bar elements to heat seal the ridges on the front and back walls. Said heated element having a desired rigid shape and configuration. In a further preferred embodiment said second set of electrodes form the handle seal and a third set of blades cuts the opening of the handle. In yet a further preferred embodiment another cutting device severs the bottom seal corners (Fig.1, 16 and 16b) between the oblique seal and the horizontal bottom seal in an oblique manner. The creasing of the bottom horizontal seal part (Fig. 8, 110) can be obtained in two ways. A mechanical embossing in the machine direction is obtained, by means of a steel wheel that folds the film just above or in the bottom seal area. The bottom seal itself can also be thermoformed to the desired shape. This can be achieved, for example, with a bottom seal tool which includes a dent, i.e. the bottom seal tool is not a flat surface.

Claims: A self standing flexible pouch for containing liquids having a top portion (FIG. 1,2) and a base portion (FIG. 1,3) comprising a front wall (FIG. 1,4) and back wall (FIG. 1,5) and a base wall (FIG. 1,6) generally perpendicular to said front and back walls when said pouch is filled in its upright position, and said front and back walls being sealed together along their top edges (FIG. 1,7 and 8) and their peripheral edges (FIG. 1:9, 10, 11, 12) only in said top portion and said bottom wall being sealed to said front and back walls, in said base portion, along their peripheral edges (FIG. 2,30,30b) and along their bottom edges ( FIG. 2,24), forming with each bottom edge a bottom horizontal seal part (FIG. 8,110), said peripheral edges (FIG. 2,30,30b) of said front and back walls and said base wall in said base portion being substantially along oblique seals, characterized in that said pouch further comprises a means to provide an outward unfolding of said bottom horizontal seal part when said pouch is filled, said means being achieved by the means selected from the group consisting of: (1) creasing said bottom horizontal seal part (FIG. 8, 110); (2) making the base wall (FIG 9, 140) of a stiffer material than for the front (FIG. 9, 120) and back walls (FIG. 9, 130); (3) creasing said bottom horizontal seal part and severing the bottom seal corners (FIG. 1,16 & 16a) between the oblique seal (FIG. 8,100) and the bottom horizontal seal (FIG. 8, 110) in an oblique manner; (4) creasing said bottom horizontal seal part and making the base wall of a stiffer material than for the front and back walls; (5) severing the bottom seal corners between the oblique seal and the bottom horizontal seal in an oblique manner and making the base wall of a stiffer material than for the front and back walls; (6) creasing said bottom horizontal seal part and severing the bottom seal corners between the oblique seal and the bottom horizontal seal in an oblique manner and making the base wall of a stiffer material than for the front and back walls. A self-standing flexible pouch according to claim 1, characterized in that the stiffer material is achieved by using a different material for the base wall (FIG. 9,140). A self-standing flexible pouch according to claim 1 or 2, characterized in that a stiffer material is achieved by laminating with a thicker structure to said base wall (FIG. 9,140). A self standing flexible pouch according to any of the preceding claims, further characterized in that the obtuse angle (FIG. 1, β) between the inner edge of the oblique peripheral seal of the front or back wall in the base portion and the perpendicular axes is between 120° and 150°. A self-standing flexible pouch according to any of the preceding claims, further characterized in that said pouch when in its upright position has at least one ridge (FIG. 1,15), preferably four ridges parallel with the perpendicular axes extending from the bottom edge corner (FIG. 1, 16, 16b) of the base portion (FIG. 1,3) to a point in the top portion (FIG. 1,2) of said pouch. A self-standing flexible pouch according to any of the preceding claims, characterized in that said pouch further comprises a handle (FIG.1,17). A method of making said self standing flexible pouch for containing liquids from material, according to any of the preceding claims which comprises the steps of: supplying a reel (FIG. 7,17) of a flattened tube of plastic material of which both edges are folded in a manner such that each edge forms a V shape, placing two anti-adhesive screens (FIG. 7, 21), the length of which is greater than the width of one pouch, said screens being disposed opposite each other inside the lateral folds of the tube. supplying a pair of electrodes (FIG. 7,22) to form the oblique seals and the longitudinal seals, supplying a second set of electrodes (FIG. 7,23) to form the lateral seals, supplying a set of blades and a cutting device, said set of blades (FIG. 7,24) cutting the tube along the median longitudinal line thereof and said cutting device severing the pouches from one another (FIG. 7,25) characterized in that another set of blades (FIG. 7,26) forms the peripheral oblique edges of the pouch by cutting substantially along the oblique peripheral seal, and in that said method comprises the step of severing the bottom seal corners (FIG. 1, 16 and 16b) with a second cutting device and/or creasing the bottom seal part (FIG. 8, 110) through a mechanical embossing or a thermoforming. A method of making said self standing flexible pouch for containing liquids from material, according to any of the preceding claims 1 to 6, which comprises the steps of: supplying a set of two reels (FIG. 5,7 and 8) of plastic material (FIG. 4,1 and 2) which are superposed, supplying a third reel (FIG. 5, 11) of plastic material (FIG. 4,3) which forms an inverted V shape between the plastic material of said set of reels, supplying a pair of electrodes (FIG. 5,14) to form the lateral seals, supplying a set of blades (FIG 5, 16 and 27) said set of blades (FIG. 5, 16) severing the pouches from one another, characterised in that another set of blades (FIG. 5,27) forms the peripheral oblique edges of the pouch by cutting substantially along the oblique peripheral seal, and in that said method comprises the step of severing the bottom seal corners (FIG. 1, 16 and 16b) with a second cutting device and/or creasing the bottom seal part (FIG. 8, 110) through a mechanical embossing or a thermoforming.

Inventors: ETESSE PATRICK JEAN-FRANCOIS, NEERGAARD ARTHUR HAMPTON, ETESSE, PATRICK JEAN-FRANCOIS, NEERGAARD, ARTHUR HAMPTON, Etesse, Patrick Jean-François
Applicants: PROCTER & GAMBLE, THE PROCTER & GAMBLE COMPANY
Application year: 1994
Main classification: B65D30
IPC codes: B65D30, B65D75, B65D33